Systems and methods for obtaining energy from surface waves

ABSTRACT

A system for obtaining energy from surface waves is disclosed. The system can include an array of buoys. The array of buoys can include a framework having a plurality of vertical members. The array of buoys can also include a base buoy coupled to the framework to support the framework in a body of water and maintain the vertical members in a vertical orientation. The array of buoys can further include a plurality of movable buoys. Each of the plurality of movable buoys can be movably disposed about a different one of the vertical members and configured to move relative to the respective vertical members and the base buoy in response to a wave in the body of water. Additionally, the array of buoys can include an energy conversion device operable with each of the plurality of movable buoys to generate power from movement of the movable buoys relative to the vertical members. In addition, the system can include a buoyant tether coupled to the array of buoys to secure the array of buoys to an object.

PRIORITY DATA

This application is a continuation of U.S. application Ser. No.15/313,586, filed Nov. 23, 2016, now issued as U.S. Pat. No. 10,309,367,which is a National Stage of International Application No.PCT/US2015/027852, filed on Apr. 27, 2015, which claims the benefit ofU.S. Application No. 62/007,822, filed on Jun. 4, 2014, each of whichare incorporated herein by reference.

BACKGROUND

The ocean has great potential for generating usable energy if it can beharnessed efficiently. For example, there are a few ways that the oceancan be used to generate useable energy, e.g., use of ocean waves, use ofocean high and low tides, and/or use of temperature differences in thewater. There are a few ocean energy power plants, but nothing on a verylarge scale. Regarding the use of ocean waves, it is known that suchwaves have a lot of kinetic energy, and this energy can be used to powervarious systems.

Although there are many systems for generating energy from the movementof ocean water, there is a continued need to find improvements in theway that this wave energy is harnessed.

SUMMARY

A system is disclosed for obtaining or generating energy from surfacewaves, such as the deep ocean. The system can include an array of buoys.The array of buoys can include a framework having a plurality ofvertical members. The array of buoys can also include a base buoycoupled to the framework to support the framework in a body of water andmaintain the vertical members in a vertical orientation. The array ofbuoys can further include a plurality of movable buoys. Each of theplurality of movable buoys can be movably disposed about a different oneof the vertical members and configured to move relative to therespective vertical members and the base buoy in response to a wave inthe body of water. Additionally, the array of buoys can include anenergy conversion device operable with each of the plurality of movablebuoys to generate power from movement of the movable buoys relative tothe vertical members through the use of any technology known in the artfor pumping water, pumping air, electromagnetic induction, or conversionthrough any other type of mechanical motion. In addition, the system caninclude a buoyant tether coupled to the array of buoys to secure thearray of buoys to an object. In another example, a method for obtainingor generating energy from a wave in a body of water can compriseobtaining an array of buoys as described herein, coupling a buoyanttether to the array of buoys, disposing the array of buoys in the bodyof water, and securing the array of buoys to an object.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an array of buoys for obtaining energy from a wave ina body of water, in accordance with an embodiment of the presentdisclosure.

FIG. 2 illustrates an array of buoys for obtaining energy from a wave ina body of water, in accordance with another embodiment of the presentdisclosure.

FIGS. 3A-3C illustrate an array of buoys in operation with waves of atypical or design size, in accordance with an embodiment of the presentdisclosure.

FIGS. 4A-4C illustrate an array of buoys in operation with waves thatexceed a typical or design wave size, such as a rogue wave, inaccordance with an embodiment of the present disclosure.

FIG. 5 illustrates an energy conversion device that is operable with amovable buoy to generate power from movement of the movable buoy, inaccordance with an embodiment of the present disclosure.

FIG. 6 illustrates an energy conversion device that is operable with amovable buoy to generate power from movement of the movable buoy, inaccordance with another embodiment of the present disclosure.

FIGS. 7A and 7B illustrate a cross configuration for maintainingstability of an array of buoys in the water, in accordance with anembodiment of the present disclosure.

FIGS. 8A and 8B illustrate a configuration for maintaining stability ofan array of buoys in the water as well as for extending the array toinclude any number of movable buoys and/or base buoys, in accordancewith an embodiment of the present disclosure.

FIG. 9 illustrates a system for obtaining energy from surface waves, inaccordance with an embodiment of the present disclosure.

FIG. 10 illustrates a system for obtaining energy from surface waves, inaccordance with another embodiment of the present disclosure.

FIG. 11A illustrates a system for obtaining energy from surface waves,in accordance with yet another embodiment of the present disclosure.

FIG. 11B illustrates the system of FIG. 11A when subjected to an extremewave.

FIGS. 12A and 12B illustrate the system of FIG. 11A aligning withvarying wind/wave directions.

FIG. 13A illustrates a system for obtaining energy from surface waves,in accordance with still another embodiment of the present disclosure.

FIG. 13B illustrates the system of FIG. 13A when at high tide.

FIG. 13C illustrates the system of FIG. 13A when subjected to an extremewave.

FIG. 14 illustrates a system for obtaining energy from surface waves, inaccordance with still another embodiment of the present disclosure.

FIGS. 15A and 15B illustrate a system for obtaining energy from surfacewaves in accordance with a further example of the present disclosure.

FIG. 16 illustrates a system for obtaining energy from surface waves, inaccordance with another embodiment of the present disclosure.

FIG. 17 illustrates a system for obtaining energy from surface waves, inaccordance with yet another embodiment of the present disclosure.

FIG. 18 illustrates a top cross-sectional view of the system of FIG. 17.

DETAILED DESCRIPTION

Reference will now be made to the exemplary embodiments, and specificlanguage will be used herein to describe the same. It will neverthelessbe understood that no limitation of the scope of the disclosure isthereby intended. Alterations and further modifications of the inventivefeatures illustrated herein, and additional applications of theprinciples of the disclosures as illustrated herein, which would occurto one skilled in the relevant art and having possession of thisdisclosure, are to be considered within the scope of the disclosure. Itis also to be understood that the terminology used herein is used forthe purpose of describing particular embodiments only. The terms are notintended to be limiting unless specified as such.

The singular forms “a,” “an,” and, “the” include plural referents unlessthe context clearly dictates otherwise. Thus, for example, reference to“a buoy” includes reference to one or more of such buoys, and referenceto “the vertical member” includes reference to one or more of suchvertical members.

As used herein, the term “about” is used to provide flexibility to anumerical range endpoint by providing that a given value may be “alittle above” or “a little below” the endpoint.

As used herein, a plurality of items, structural elements, compositionalelements, and/or materials may be presented in a common list forconvenience. However, these lists should be construed as though eachmember of the list is individually identified as a separate and uniquemember. Thus, no individual member of such list should be construed as ade facto equivalent of any other member of the same list solely based ontheir presentation in a common group without indications to thecontrary.

Numerical data may be expressed or presented herein in a range format.It is to be understood that such a range format is used merely forconvenience and brevity and thus should be interpreted flexibly toinclude not only the numerical values explicitly recited as the limitsof the range, but also to include all the individual numerical values orsub-ranges encompassed within that range as if each numerical value andsub-range is explicitly recited. As an illustration, a numerical rangeof “about 1 to about 5” should be interpreted to include not only theexplicitly recited values of about 1 to about 5, but also includeindividual values and sub-ranges within the indicated range. Thus,included in this numerical range are individual values such as 2, 3, and4 and sub-ranges such as from 1-3, from 2-4, and from 3-5, etc., as wellas 1, 2, 3, 4, and 5, individually. This same principle applies toranges reciting only one numerical value as a minimum or a maximum.Furthermore, such an interpretation should apply regardless of thebreadth of the range or the characteristics being described.

In accordance with these definitions and embodiments of the presentdisclosure, a discussion of the various systems and methods is providedincluding details associated therewith. This being said, it should benoted that various embodiments will be discussed as they relate to thesystems and methods. Regardless of the context of the specific detailsas they are discussed for any one of these embodiments, it is understoodthat such discussion relates to other all other embodiments as well.

The present disclosure is drawn to a system for obtaining or generating(converting) energy from surface waves in a body of water. The systemcan comprise an array of buoys, which can include a framework having aplurality of vertical members. The array of buoys can also include abase buoy coupled to the framework to support the framework in a body ofwater and maintain the vertical members in a vertical orientation.Furthermore, the array of buoys can include a plurality of movablebuoys, wherein each of the plurality of movable buoys is movablydisposed about a different one of the plurality of vertical members andconfigured to move relative to the respective vertical members and thebase buoy in response to a wave in the body of water. Additionally, thearray of buoys can include an energy conversion device operable witheach of the plurality of movable buoys to generate power from movementof the movable buoys relative to the vertical members. In addition, thesystem can include a buoyant tether coupled to the array of buoys tosecure the array of buoys to an object.

In another embodiment, the disclosure provides a method for obtaining orgenerating (converting) energy from a wave in a body of water. Themethod can comprise obtaining an array of buoys, the array of buoysincluding a framework having a plurality of vertical members, a basebuoy coupled to the framework to support the framework in a body ofwater and maintain the vertical members in a vertical orientation, aplurality of movable buoys, wherein each of the plurality of movablebuoys is movably disposed about a different one of the plurality ofvertical members and configured to move relative to the respectivevertical members and the base buoy in response to a wave in the body ofwater. An energy conversion device operable with each of the pluralityof movable buoys to generate power from movement of the movable buoysrelative to the vertical members can also be included. The method canalso comprise coupling a buoyant tether to the array of buoys, disposingthe array of buoys in the body of water and securing the array of buoysto an object. The buoyancy of the tether can be such that the tether isessentially self-supportive in the water and does not drag down orotherwise interfere with the array of buoys when in use.

FIG. 1 shows an array of buoys 100 for obtaining energy from a wave 101in a body of water. The array of buoys can include a framework 110having a plurality of vertical members 111, 112, 113. The array of buoyscan also include a base buoy 120 coupled to the framework to support theframework in the body of water and maintain the vertical members in avertical orientation. In one aspect, the base buoy can be fixedlyattached to the framework at or near a center of the framework, such asto a middle or primary column, to effectively support the framework inthe water. The array of buoys can also include a plurality of movablebuoys 130, 131, such that each of the plurality of movable buoys ismovably disposed about a different one of the plurality of verticalmembers, such as an outer column, and configured to move relative to therespective vertical members and the base buoy in response to a wave inthe body of water. In one aspect, the movable buoys can be configured tofreely move or slide up and down relative to the vertical members andthe base buoy. An energy conversion device can also be included and canbe operable with each of the plurality of movable buoys to generatepower from movement of the movable buoys relative to the verticalmembers.

It is noted that the embodiment shown in FIG. 1 as well as in FIGS. 2-4c hereinafter may or may not be inherently stable in the ocean, asadditional stabilizing structures would typically be included tomaintain the vertical members in a generally vertical configuration.These devices are shown in this manner without one or more of the manypossible stabilizing structures that could be used in order to moreclearly illustrate how the device functions at a basic level. Certaindevices that may be more stable in the waves of the ocean are shown byexample in FIGS. 7A-8B, and there are many other stable configurationsthat could likewise be devised that utilize the basic structure shown inFIGS. 1-4 c. Furthermore, it is noted that the term “vertical” isdefined as being generally vertical with respect to the construction ofthe framework as the device sits in the water. As waves pass by thedevice, the “vertical” members will not remain completely vertical atall times, but as mentioned, will be generally vertical in orientation.

With reference to FIG. 2, and continued reference to FIG. 1, an array ofbuoys 200 for obtaining energy from a wave in a body of water can beconfigured based on relationships to typical (design) wave expected tobe encountered by the array of buoys. For example, it has been observedthat typical deep water waves have a reasonably constant wave height anda wavelength relationship. Specifically, for a given wave height (×),the wave length is about seven times (7×) the wave height from peak totrough. In one aspect, the array of buoys can be designed for a specificwave height where the range of motion of the movable buoys relative tothe vertical members is about two times (2×) the wave height. The basebuoy can be configured to support the framework in the water tofacilitate movement of the movable buoys up to two times the design waveheight. In addition, the distance between the base buoy and a movablebuoys can be from about two times the wave height (2× or 2:1 ratio) toabout five times the wave height (5× or 5:1 ratio). In one particularaspect, the distance between the base buoy and a movable buoys is aboutthree-and-a-half times the design wave (3.5× or 3.5:1 ratio). In thisconfiguration, the base buoy can support the framework in the water suchthat the vertical floating movement of the movable buoys relative to thevertical members of the framework can move up to two times the designwave height.

The array of buoys can be used to obtain energy from water waves toproduce energy through pumping water, pumping air, induction, orconversion through any other type of mechanical motion since eachmovable buoy can have attached to it an energy conversion device knownin the art for converting mechanical motion into energy, such as a pumpor electrical generator. It should be recognized that although the arrayof buoys can be designed for deep ocean water waves, other waves canalternatively be utilized.

In addition, each vertical member 211, 213 can have a height of twotimes (2×) the design wave height plus lengths 214 a, 214 b toaccommodate variables such as the movable buoy height as well as asafety distance to provide additional clearance to minimize the chanceof impact due to the fact that it is unlikely that each movable buoywill always float with the water exactly in the middle of the buoyheight. Energy conversion devices 240 a, 240 b can be operable with themovable buoys 230, 231 to generate power from movement of the movablebuoys relative to the vertical members.

A tether 215 can be coupled to the framework 210 to anchor the array ofbuoys 200 to an object, such as an ocean floor 203 or to an object 204floating on a surface of the body of water such as a boat or oil rig.The tether can be configured to allow the array of buoys to moveeffectively in the water on the waves without permitting the array ofbuoys to stray too far from a desired location.

In one aspect, the array of buoys 200 can include a locomotion device250 operable to move the array of buoys through the body of water. Thelocomotion device can be used to move the array of buoys to a desiredlocation and/or to maintain the array of buoys at a desired position.For example, the locomotion device can be used to move the array ofbuoys from a deployment location, such as a dock, to a deep waterlocation for harvesting energy. In one aspect, locomotion device can bealso used to provide movement for a ship or other water vessel bycoupling the array of buoys to the ship.

The array of buoys 200 can also include various systems useful foroperating the array of buoys, such as a control system 260 operable tocontrol operation of the array of buoys, a communication system 262operable to communicate with a command center or base station, and/or aglobal positioning system (GPS) 264. For example, the control system canmonitor various aspects of the array of buoys, such as the amount ofenergy generated. The communication system can communicate with a base266, such as a command center located on land or on a ship. The GPS canmonitor location of the array of buoys. Thus, the command center canreceive data from the array of buoys as well as give operatinginstructions, such as a location to move to, etc. In response to suchinstructions, the locomotion device 250 can move the array of buoys to alocation using the GPS for navigation.

The array of buoys 200 can be constructed of any suitable material. Forexample, typical structural materials suitable for marine use may beused, particularly those suitable for salt water applications whencontemplating use in the ocean. In addition, the array of buoys can usehydrophobic materials on its surfaces so that any ice that forms duringcold weather will shear and fall off the buoys and the framework as thearray of buoys moves in the ocean, thereby preventing ice buildup.

FIGS. 3A-3C illustrate an array of buoys 300 in operation with waves ofa typical or design size. For example, as shown in FIG. 3A, the twomovable buoys 330, 331 on opposite sides of the base buoy 320, at adistance from the base buoy as outlined above, are able to be at thelowest points, or troughs of a wave, while the base buoy 320 is at ahighest point, or a crest of the wave. FIG. 3B shows the wave moving indirection 302 and causing the base buoy to fall off the crest while themovable buoys ride up out of the troughs toward crests. When the wavemoves a distance of three-and-a-half wave heights, as shown in FIG. 3C,the movable buoys have switched vertical positions so that the movablebuoys are at crests of a wave and the base buoy is at a trough. Thiscreates a total vertical movement for each movable buoy along thevertical member associated with the movable buoy of two times the waveheight.

FIGS. 4A-4C illustrate an array of buoys 400 in operation with wavesthat exceed a typical or design wave size, such as a rogue wave. Forexample, as shown in FIG. 4A, the base buoy 420 lifts the entire arrayof buoys up on the crest of the wave, with the two movable buoys 430,431 on opposite sides of the base buoy 420 on either side of the crestof the wave. FIG. 4B shows the wave moving in direction 402 and causingthe array of buoys to fall off the crest of the wave. The movable buoysfloat on the wave such that movable buoy 430 tends to rise relative tothe vertical member of the framework while movable buoy 431 tends tofall relative to the vertical member of the framework. In the event thatthe framework becomes unstable, the framework may tip causing themovable buoy to rise up the vertical member until it has reached the endof the range of motion, at which point it will prevent further tippingof the framework. Thus, the array of buoys can effectively ride up ordown a large wave without tipping over. As shown in FIG. 4C, upon thebase buoy reaching the trough of the wave, the movable buoys have movedup relative to the vertical members. The array of buoys can operate inany size wave by riding the slope of the wave and can therefore keepoperating through hurricanes and tsunamis without damage. No matter howhigh the waves get, the buoys can keep floating and move withoutcollision or damaging movement. No braking method or stop motion isrequired for extremely large ocean waves.

The array of buoys can produce the same amount of energy whenever theocean waves are higher than or equal to the designed wavelength for thearray. This permits a system to be designed for a specific capacitywithout wide fluctuations in performance as long as the actual waveheight is greater than or equal to the wave height for which the array 1has been designed. Such attributes are attractive for using an array ofbuoys as primary power, replacing nuclear, petroleum, natural gas, orcoal plants. There is no need to vary the size of the framework toaccommodate ocean depth differences which impacts other ocean wavedevices which are attached to the ocean floor. Every device can be thesame, thereby creating cost savings and improving manufacturability. Inaddition, because the entire array of buoys floats, operation in deepocean waves is enabled. This allows placement of the device far fromland so that deep ocean waves, which are larger than those close toshore, can be harvested for energy, and avoids cluttering the coastalwaterways or taking up real estate used for tourism.

FIG. 5 illustrates an example of an energy conversion device 540 that isoperable with a movable buoy 530 to generate power from movement of themovable buoy relative to a vertical member 511. In this example, theenergy conversion device comprises an inductor that generateselectricity via electromagnetic induction. The inductor includes a coil541 of conducting material, such as copper wire. The vertical member 511includes a ferromagnetic or ferromagnetic material within the range ofmotion of the movable buoy to form a core 512 for the inductor. Thus,relative motion of the movable buoy causes the coil to move relative tothe core and generating electricity. The electricity can be used orstored, indicated at block 513, as desired.

FIG. 6 illustrates another example of an energy conversion device 640.In this example, the energy conversion device comprises a pump thatutilizes a piston 641 coupled to a vertical member 611 that moves withina cylinder 642 associated with a movable buoy 630. The pump includesone-way inlet valves 643 a, 643 b and outlet valves 644 a, 644 b toregulate the flow of water through the pump. The pump can be configuredto have a maximum stroke of two times the design wave height, which canbe limited by stops 612 a, 612 b on the vertical member. Thus, relativemotion of the movable buoy causes the piston to move relative to thecylinder and pumping water. The pumped water can be used to generateelectricity, to turn a propeller for locomotion of the array of buoys,to provide water pressure for locomotion via water jets, to pump waterout of flood zones for hurricane protection, or any other suitable useas desired, indicated at block 613.

For the hydroelectric generation of energy, water can be pumped from oneor more arrays of buoys to a floating hydroelectric generator or pumpedto a land-based hydroelectric generator. Water can be pumped up into afloating water tower (so that many small pumps can pump water withoutworking against each other) to provide water pressure for thehydroelectric generator. This option would, for example, allow the quickconversions of troubled or deficient energy sources, to ocean waveenergy. For example, many nuclear reactors are built close to the coast.For these reactors, water from ocean waves can be pumped to turnexisting generators which were initially designed to be run by steamproduced by a nuclear reactor. These generators can be converted to runas a result of pumped water. For desalination plants, water can bepumped from one or more arrays of buoys to a reverse osmosis plant tocreate fresh water from salt water. Also, the array of buoys can be usedto provide remote power to oil rigs, undeveloped areas, and locationswhere disaster relief is needed.

It is noted that if the desire is to pump water using the systems andmethods described herein, a combination of an electricity generator (asin FIG. 5) can be used to generate electricity by induction, and theelectrical power can be used to run a conventional water pump. This maybe a more simple way of moving water, rather than having morecomplicated pistons, one way valves, etc., described with respect toFIG. 6.

FIGS. 7A and 7B illustrate a cross configuration for maintainingstability of an array of buoys 700 in the water. Here, the base buoy 720and the plurality of movable buoys 730 a, 731 a, 730 b, 731 b arearranged in a cross configuration with the base buoy disposed at acenter of the cross configuration. The cross configuration locatesmovable buoys extending out in four opposite directions from the basebuoy to provide floatation stability for the array of buoys. The crossconfiguration also enables energy harvesting vertical motion of themovable buoys from waves encountering the array of buoys from multipledirections.

FIGS. 8A and 8B illustrate a configuration for maintaining stability ofan array of buoys 800 in the water as well as for extending the array toinclude any number of movable buoys and/or base buoys. For example, abase buoy 820 a can be associated with one or more movable buoys 830 a,831 a in a positional relationship as disclosed herein. This basicarrangement can be repeated any number of times to expand or enlarge thearray, as illustrated with base buoys 820 b and 820 c, and movable buoys830 b, 831 b and 830 c, 831 c, respectively. The base buoys can serve asstabilizing buoys for the array. The base buoys can be connected by oneor more framework members, such as lateral members 816 a, 816 b.Alternatively, or in addition, the base buoys can be connected by one ormore lateral framework members 817 a, 817 b that extend betweenframework portions proximate to movable buoys. In one aspect, thelateral framework members connecting base buoys can form rigidconnections or pivoting connections. A pivoting connection may result inreduced stress on the framework as an array grows in size by allowingthe base members to move relative to one another to follow a wavewithout suspending a base member in the air above the water. In thiscase, a range of motion for a pivoting connection can be limited toprevent the framework from folding up and collapsing or damagingcomponents of the array. It should be appreciated that the variouscomponents of an array of buoys can be arranged to provide stabilityand/or expand the number of base buoys and/or movable buoys in the arrayutilizing the concepts and positional relationships disclosed herein.

FIGS. 9 and 10 each illustrate a system for obtaining energy fromsurface waves, comprising an array of buoys coupled to a buoyant tether,which can be used to secure or attach an array of buoys to an object,such as the ocean floor or a floating support of some type, such as aship or oil rig. A buoyant tether as disclosed herein can thereforeserve as a mooring line, a tow line, or any other suitable type oftether.

FIG. 9 illustrates a system 905 having an array of buoys 900 coupled toa tether 940 and secured or attached to an object 903, similar to thatshown in FIG. 2. However, in this example, the tether is a buoyanttether which includes a plurality of attached buoyancy devices 941, 942,943, 944, 945 coupled along the length of the buoyant tether. Otherstructures are similar to those previously described, such as in FIGS.1-4C. In FIG. 9, however, the attached buoyancy devices can beconstructed of any suitable buoyant material and can be coupled to thebuoyant tether at any position. By contrast, the buoyant tether need notcomprise attached buoyancy devices, but can comprise built in buoyancy.In one aspect, the buoyant tether 940 can be coupled to the array ofbuoys 900 via a framework 910 of the array of buoys.

In further detail, the buoyant tether 940 can comprise a cable or autility line. The utility line can transfer electricity, pumped fluid,or gas to or from the array of buoys. In very deep water, a very longcable or utility line might otherwise exert considerable drag on thearray of buoys, which could reduce the movement of the moveable buoysand thereby reduce the amount of energy captured by the array of buoys.The mass of the cable or utility line can be supported by built inbuoyancy or attached buoyancy devices. Such support will reduce the peakload which would exist at the top of the cable or utility line where itconnects to the array of buoys, which can thereby increase the life ofthe cable or utility line and reduce the risk of breakage or otherdamage during rough weather. In further detail regarding the buoyanttether, by providing a self-supporting tether in the water with respectto its own weight or mass, movable buoys of the array of buoys can movewith freedom up and down with the ocean waves without losing momentum,e.g., a heavy or non-buoyant tether may cause the array of buoys to bebeing forced into a submersed or partially submersed state, diminishingthe effectiveness of the device.

FIG. 10 illustrates a system 1005 having an array of buoys 1000 coupledto a buoyant tether 1040, again, similar to that shown in FIG. 2.However, in this example, the buoyant tether 1040 comprises a primarybuoyant tether 1050 a and a plurality of secondary buoyant tethers 1050b and 1050 c which act to secure the array of buoys to an object 1003.In this example, the secondary buoyant tethers 1050 b, 1050 c arecoupled to the primary buoyant tether 1050 a via a tensioner 1060, whichcan facilitate load sharing among the secondary tethers. The tensioner1060 can include a bungee cord, spring, shock, etc. attached across aloop in the tether cable allowing force from a base buoy 1020 to pullthe bungee cord, spring, or shock to release additional line for thetether, thus facilitating a change in the tether length, which can allowadjustment of the tether to compensate for changing ocean height due towaves and tides. As illustrated, the primary buoyant tether and theplurality of secondary buoyant tethers are supported by attachedbuoyancy devices 1041, 1042, 1043, 1044, 1045, 1046, and 1047. Theattached buoyancy devices can be constructed of any suitable buoyantmaterial. Further, at least one of the primary buoyant tether and thesecondary buoyant tethers can be constructed of buoyant material orcomprise built in buoyancy.

The tensioner 1060 can couple the primary buoyant tether 1050 a to theplurality of secondary buoyant tethers 1050 b, 1050 c. During storms andrough ocean waves, large wind loads, currents, and/or wave action, thearray of buoys can be battered about. Some larger arrays of buoys canbenefit from multiple tethers to reduce the peak loads on the tether asa whole and to prevent breakage and loss of moorings. Attaching one ormore tensioners to the primary buoyant tether enables the system 1005 toload share the force across a plurality of secondary buoyant tethers. Infurther detail, there can be multiple tethers that couple at differentlocations on the array of buoys, or can couple to separate arrays ofbuoys, either through a tensioner or directly to the object or oceanfloor. Each tether can have its own electrical connection to an inductorof an energy conversion device, or the tethers can be connectedelectrically together, such as in series or in parallel.

FIG. 11A illustrates a system 1105 for obtaining energy from surfacewaves in accordance with another example of the present disclosure. Aswith other examples described herein, the system 1105 can include anarray of buoys 1100 and a buoyant tether 1140 coupled to the array ofbuoys. In this case, the buoyant tether can include a lateral tetherportion 1151 coupled to the array of buoys, a vertical tether portion1152 to attach to an object 1103 (e.g., a mooring line to the oceanfloor), and a lateral support buoy 1153 coupled between the lateraltether portion and the vertical tether portion. The buoyant tether canbe coupled to the array of buoys via a framework 1110 and/or a base buoy1120 of the array of buoys. In one aspect, the lateral support buoy 1153can substantially provide buoyancy for the lateral tether and/or thevertical tether. Thus, the lateral support buoy 1153 can support theweight of a tether/utility line going to the ocean floor. Wavespropagating in direction 1102 can cause the array of buoys 1100 to beoriented away from the lateral support buoy 1153, thus extending thelateral tether portion substantially horizontal in the same directiondue to the attachment of the vertical tether portion 1152 to the oceanfloor. Running the lateral tether portion from the array of buoys 1100horizontally to the lateral support buoy can allow the array of buoys to“fly” on the ocean surface much like a kite on the wind, allowingmovement of the array of buoys with the ocean waves in a substantiallyvertical direction, which is in the same direction as buoyant forcesacting on the buoys. This tethering configuration can therefore closelyalign the buoy motion with the direction of buoyant forces acting on thebuoys. This tethering configuration can have advantages over othertethering configurations. For example, in some tethering configurations,an array of buoys is tethered directly or straight downward to the oceanfloor (see, e.g., FIG. 2) causing the array of buoys to support at leastsome of the mass of the tether, which creates a resistance forcecountering the up/down movement of buoyant forces causing the buoy totilt at an angle. Supporting the vertical or mooring tethering portion1152 with the lateral support buoy 1153, as in FIG. 11A, can reduce orminimize the tilting effect or misalignment of buoy movement and buoyantforce direction, such as can occur with other tethering configurations.In one aspect, as described above, the lateral tether 1151 and/or thevertical tether 1152 can comprise an attached buoyancy device coupledthereto and/or have built in buoyancy.

FIG. 11B illustrates the system 1105 when subjected to an extreme wave.As shown in the figure, by having the lateral tether portion 1151coupled to the tether support buoy 1153, which is coupled to the oceanfloor 1103 via the vertical tether portion 1152, the array of buoys 1100can be prevented from “surfing” down the slope of the wave and snappingthe tether line at the bottom of the wave. With this configuration,slack in the lateral tether portion 1151 is removed as the array ofbuoys 1100 rides a wave, thus preventing or minimizing horizontalspeed/motion of the array of buoys. The lateral tether portion 1151 cantherefore hold the horizontal position of the array of buoys 1100 andcounteract the surfing force acting on the array of buoys caused by thewave propagating in direction 1102. The lateral tether portion 1151 canalso hold the leading edge of the array of buoys 1100 so that breakingwaves will crash over and not lift up or flip the array of buoys.

Although the tether configuration illustrated in FIGS. 11A and 11B canhelp the array of buoys survive an extreme wave, a site survey can beperformed, such as through archives and satellite data, to identifyareas that are prone to extreme waves (i.e., waves greater than 30 mtall with unusually steep slopes) so that power production sites can belocated in areas where there is a lower risk of an extreme wave.

The tether configuration illustrated in FIGS. 11A and 11B can alsofacilitate alignment of the tether 1140 and the array of buoys 1100 withthe direction of waves (i.e. currents) and/or wind. For example, asshown in the top view of the system 1105 in FIG. 12A, due to theanchoring location of the system being substantially below the lateralsupport buoy 1153, wind/waves in direction 1102 a can orient the system1105 such that the tether 1140 and the array of buoys 1100 are alignedwith the wind/waves. As the wind/waves change to direction 1102 b, asshown in FIG. 12B, the system 1105 can pivot about the anchoring pointlocated below the lateral support buoy 1153 such that orientation of thesystem can align with the wind/wave direction 1102 b.

FIG. 13A illustrates a system 1205 for obtaining energy from surfacewaves in accordance with yet another example of the present disclosure.As with other examples described herein, the system 1205 can include anarray of buoys 1200 and a buoyant tether 1240 a coupled to the array ofbuoys. In this case, another buoyant tether 1240 b can also be coupledto the array of buoys to provide additional stability when coupling toan object 1203, such as an ocean floor. The buoyant tethers 1240 a, 1240b can be of similar configuration, having lateral tether portions 1251a, 1251 b coupled to the array of buoys, vertical tether portions 1252a, 1252 b to attach to the ocean floor, and lateral support buoys 1253a, 1253 b coupled between the second lateral tether portions and thesecond vertical tether portions. As shown in the figure, the buoyanttethers 1240 a, 1240 b are coupled to the array of buoys about oppositesides, although the buoyant tethers can be in any suitable relativeposition when coupled to the array of buoys.

In one aspect, FIG. 13A can represent the system 1205 when the ocean isat low tide. In this case, the lateral support buoys 1253 a, 1253 b canbe just under the water level with the vertical tether portions 1252 a,1252 b in a vertical orientation. FIG. 13B can represent the system 1205when the ocean is at high tide. In this case, the lateral support buoys1253 a, 1253 b can lean in toward the array of buoys 1200 changing theorientation of the vertical tether portions 1252 a, 1252 b from vertical(FIG. 13A) to an angle 1254 off of vertical (FIG. 13B) by keeping thetethers 1240 a, 1240 b under tension and reducing or eliminating slackthat may exist in the tethers as wave conditions change from low to hightide. A length of the lateral tether portions 1251 a, 1251 b can beincreased to improve performance.

FIG. 13C illustrates the system 1205 when subjected to an extreme wave.As with the system 1105 illustrated in FIG. 11B, the lateral buoyanttether 1240 a of the system 1205 can be configured to hold thehorizontal position of the array of buoys 1200 and counteract thesurfing force acting on the array of buoys caused by the wavepropagating in direction 1202. In this case, the buoyant tether 1240 bcan go slack, or a tensioner can reduce the length of tether toeliminate the slack, while the wave passes the tether 1240 b and thearray of buoys is being supported by the tether 1240 a. The verticaltether portion 1252 b can float if configured with buoyant devices or ifit has built in buoyancy. In one aspect, the buoyant tethers 1240 a,1240 b can provide support for the array of buoys 1200 against wavespropagating in different directions.

FIG. 14 illustrates a system 1305 for obtaining energy from surfacewaves in accordance with still another example of the presentdisclosure. In this case, the system 1305 includes multiple arrays ofbuoys 1300 a-e coupled to one another with lateral tethers 1355 a-d in alinear arrangement. The lateral tethers 1355 a-d can be attached to thearray of buoys at interior or center members of the frameworks and/or tooutside members of the frameworks. One or more buoyant tethers can becoupled to the arrays of buoys. For example, buoyant tethers 1340 a,1340 b can be coupled to the arrays of buoys 1300 a, 1300 e,respectively, at opposite ends of the linear arrangement to providesupport for the multiple arrays of buoys 1300 a-e against a wave, suchas a wave propagating in direction 1302. In one aspect, the buoyanttethers 1340 a, 1340 b can provide support for the multiple arrays ofbuoys 1300 a-e against waves propagating in different directions.

FIGS. 15A and 15B illustrate a system 1405 for obtaining energy fromsurface waves in accordance with a further example of the presentdisclosure. The system 1405 includes multiple arrays of buoys 1400 a-ccoupled to one another with lateral tethers 1455 a-b in a linear orend-to-end arrangement. Buoyant tethers 1440 a, 1440 b can be coupled tothe arrays of buoys 1400 a, 1400 c, respectively, at opposite ends ofthe linear or end-to-end arrangement to provide support for the multiplearrays of buoys 1400 a-c against a wave, such as a wave propagating indirection 1402 a as shown in FIG. 15A. In one aspect, the buoyanttethers 1440 a, 1440 b can be configured to facilitate orientation oralignment of the multiple arrays of buoys 1400 a-c with the wind andincoming wave direction. For example, the buoyant tether 1440 b can belocated downwind from the buoyant tether 1440 a. The downwind buoyanttether 1440 b (e.g., a vertical tether portion) can be provided withmore length or slack than the buoyant tether 1440 b (e.g., the verticaltether portion) located upwind. The additional length or slack of thedownwind buoyant tether or vertical tether portion can facilitatemovement of the multiple arrays of buoys due to wind and wave movementthat can allow the multiple arrays of buoys to realign or reorient withchanging wind and wave directions. As shown in FIG. 15B, the wind/wavescan change to direction 1402 b, thus causing the arrays of buoys to movein direction 1406 away from the original orientation axis 1407 until theslack in the buoyant tether 1440 b, which may come from the verticaltether portion 1452 b, is removed. The arrays of buoys and buoyanttethers can then assume a generally arcuate shape between the anchorpoints on the ocean floor according to the drag forces on the variouscomponents of the system from the wind/waves.

FIG. 16 illustrates a system 1505 for obtaining energy from surfacewaves in accordance with another example of the present disclosure. Thesystem 1505 includes multiple arrays of buoys 1500 a-f coupled to oneanother with lateral tethers 1455 a-g in a grid arrangement orconfiguration. Buoyant tethers 1440 a-j can be coupled to the arrays ofbuoys about a perimeter of the grid arrangement. In particular, thebuoyant tethers 1540 a-c are disposed opposite the buoyant tethers 1540d-f, respectively, and the buoyant tethers 1540 g-h are disposedopposite the buoyant tethers 1540 i-j, respectively. In thisconfiguration, lateral tether portions 1551 a-f can be orientedsubstantially orthogonal to lateral tether portions 1551 g-j, which canprovide support for the arrays of buoys in multiple directions.

FIG. 17 illustrates a system 1605 for obtaining energy from surfacewaves in accordance with yet another example of the present disclosure.As with other examples described herein, the system 1605 can include anarray of buoys 1600 and a buoyant tether 1640 coupled to the array ofbuoys. In this case, the buoyant tether is shown illustrated as ifcoupled to an object, such as a boat or other such object that ismovable through water to tow the array of buoys. It should be recognizedthat any suitable buoyant tether may be utilized as described herein. Insome embodiments, the tether may not be buoyant, but may be a standardtow line.

In one aspect, one or more of a base buoy 1620 and movable buoys 1630,1631 of the array of buoys 1600 can comprise a hydrodynamic surface toreduce drag as water passes around the buoy, as shown in a topcross-sectional view A-A in FIG. 18. A hydrodynamic surface can comprisebow portion 1632 at a leading end of the buoy and a stern portion 1633at a trailing end of the buoy. A length of the bow portion and the sternportion can be different (i.e., short bow portion and long sternportion) to facilitate orienting the array of buoys. In one aspect, allbuoys of the array of buoys can include such hydrodynamic surfacefeatures and can be oriented in the same direction, as shown in FIG. 18,which can reduce or minimize the forces from the surf or breaking waveson the array of buoys.

With further reference to FIG. 17, the array of buoys 1600 can alsoinclude a ballast portion 1670 operable with the base buoy 1620 to movein a “pendulum motion” in direction 1608 in response to a wave in thebody of water. The ballast portion can provide stability (e.g.,rotational stability) for the array of buoys such that the array ofbuoys tends to restore itself to an equilibrium position after a smallangular displacement. As illustrated in the figure, the ballast portion1670 can be disposed below the base buoy 1620, such that the base buoyis substantially maintained above the ballast portion. Examples ofballast portions can be found in U.S. Provisional Patent Application No.62/065,928, filed Oct. 20, 2014, which is incorporated herein byreference. Including the ballast portion 1670 with the array of buoyscan enable the array of buoys to remain in, or return to, a desiredoperational orientation even when subjected to forces (e.g., waves)tending to tip or rotationally displace the array of buoys. The ballastportion 1670 can therefore be utilized in any array of buoys to maintainwave energy harvesting functionality throughout a variety of adverseconditions. Such a design element can be utilized to control “wiggle” ofthe array of buoys by providing enough negative stability so that thearray of buoys will move for effective operation in harvesting waveenergy, but with enough positive stability so that the array of buoyswill right itself and maintain a desired functional orientation.

An extension member 1671 can be coupled to the base buoy 1620 (e.g., viathe framework 1610) and the ballast portion 1670 to suspend the ballastportion below the base buoy. In one aspect, the extension member can beextendable and retractable in direction 1609 a to vary a distancebetween the ballast portion and the base buoy, thus varying orcontrolling the stability of the array of buoys. For example, moving theballast portion upward can reduce stability and provide for a fasterresponse and moving the ballast portion downward can increase stabilityand provide for a slower response.

In one aspect, the ballast portion 1670 can be configured as a rudder tofacilitate turning or guiding the array of buoys 1600 in the water, suchas into the direction of the waves. For example, the ballast portion canbe rotatable in direction 1609 b, such as by a motor 1672, to act as arudder and guide or steer the array of buoys. The ability to steer thearray of buoys can be useful when the array of buoys is being towed by aship, as the array of buoys can turn with the ship for more for moreeffective towing and avoidance of obstacles.

In one aspect, vertical members 1611, 1613 of the framework 1610 and themovable buoys 1630, 1631 can be configured to maintain an orientation ofthe movable buoys relative to the vertical members. For example, asshown in FIG. 18, the vertical members and the movable buoys can have aninterfacing geometry 1634 that resists rotation of the movable buoysabout the vertical members, such as due to a wave. As illustrated, sucha geometrical relationship is provided by a generally circularcross-section with a flat portion 1635 on one side. The flat portion canbe ground or machined into a structure having a circular cross-section.In this case, the flat portions are located on back sides of thevertical members or, in other words, on sides opposite the direction oftravel as identified by the location of the bow (front) and stern (rear)portions 1632, 1633 of the buoys. Such a configuration can provide lowfriction for vertical movement of the buoys while resisting rotation ofthe buoys due to lateral forces that may occur due to waves. It shouldbe recognized that any suitable interfacing geometrical configurationcan be utilized, such as a rectangular cross-section. The base buoy 1620can be fixed relative to the vertical member 1612 by a fastener 1636 orother suitable device. The interfacing geometry can transition to adifferent shape at transition features 1618, 1619. Such transitionfeatures can serve as stops to vertical movement of the movable buoysalong the vertical members. In one aspect, the transition features canbe configured to bind or wedge the movable buoys when enough force isapplied. This can prevent additional movement or operation of themovable buoys in the event of a severe storm or wave event until serviceor maintenance can be provided, which can minimize the risk of damage tothe array of buoys in extreme conditions.

Preventing rotation of the movable buoys 1630, 1631 about the verticalmembers 1611, 1613 can be particularly beneficial when the movable buoysare configured with hydrodynamic surfaces, such as the bow and sternportions 1632, 1633. The absence of such relative rotation can also bebeneficial, even when the movable buoys lack such hydrodynamic surfaces,to prevent tangling of a utility or feed line 1680, which may be coupledto the array of buoys 1600, due to spinning or rotating movable buoys.For example, utility or feed lines can be used to deliver power from apower generator associated with the movable buoys to a transmissionline, which may be located underwater. Examples of such utility or feedlines can be found in U.S. patent application Ser. No. 14/600,456, filedJan. 20, 2015, which is incorporated herein by reference.

In a related embodiment, a method for obtaining energy from a wave in abody of water in accordance with the principles herein is disclosed. Themethod can include obtaining an array of buoys including a frameworkhaving a plurality of vertical members, a base buoy coupled to theframework to support the framework in a body of water and maintain thevertical members in a vertical orientation, a plurality of movablebuoys, wherein each of the plurality of movable buoys is movablydisposed about a different one of the plurality of vertical members andconfigured to move relative to the respective vertical members and thebase buoy in response to a wave in the body of water, and an energyconversion device operable with each of the plurality of movable buoysto generate power from movement of the movable buoys relative to thevertical members. The method can also include coupling a buoyant tetherto the array of buoys. The method can further include disposing thearray of buoys in the body of water. Additionally, the method caninclude securing the array of buoys to an object.

In one aspect of the method, the buoyant tether can comprise a lateraltether portion to couple to the array of buoys, a vertical tetherportion to attach to an ocean floor, and a lateral support buoy coupledbetween the lateral tether portion and the vertical tether portion. Itis noted that no specific order is required in this method, thoughgenerally in one embodiment, these method steps can be carried outsequentially.

Of course, it is to be understood that the above-described arrangementsare only illustrative of the application of the principles of thepresent disclosure. Numerous modifications and alternative arrangementsmay be devised by those skilled in the art without departing from thespirit and scope of the present disclosure and the appended claims areintended to cover such modifications and arrangements. Thus, while thepresent disclosure has been described above with particularity anddetail in connection with what is presently deemed to be the mostpractical embodiments of the disclosure, it will be apparent to those ofordinary skill in the art that numerous modifications, including, butnot limited to, variations in size, materials, shape, form, function andmanner of operation, assembly and use may be made without departing fromthe principles and concepts set forth herein.

What is claimed is:
 1. A system for obtaining energy from surface waves,comprising: an array of buoys including a framework having a pluralityof vertical members, a base buoy coupled to the framework to support theframework in a body of water and maintain the vertical members in avertical orientation, a plurality of movable buoys, wherein each of theplurality of movable buoys is movably disposed about a different one ofthe plurality of vertical members and configured to move relative to therespective vertical members and the base buoy in response to a wave inthe body of water, and an energy conversion device operable with each ofthe plurality of movable buoys to generate power from movement of themovable buoys relative to the vertical members; and a buoyant tethercoupled to the array of buoys to secure the array of buoys to an object,the buoyant tether including a tensioner adapted to facilitate a changein length of the buoyant tether between the array of buoys and theobject to compensate for changing ocean height due to waves and tides,wherein the buoyant tether comprises a primary buoyant tether and aplurality of secondary tethers coupled to the primary tether via thetensioner to facilitate load sharing among the secondary tethers.
 2. Thesystem of claim 1, wherein the buoyant tether is a utility line carryingat least one of electricity, pumped fluid, or gas.
 3. The system ofclaim 1, wherein the buoyant tether comprises an attached buoyancydevice coupled thereto.
 4. The system of claim 1, wherein the buoyanttether has built in buoyancy.
 5. The system of claim 1, wherein thebuoyant tether is coupled to the array of buoys via at least one of theframework and the base buoy.
 6. The system of claim 1, wherein thebuoyant tether comprises: a lateral tether portion coupled to the arrayof buoys; a vertical tether portion to attach to an ocean floor; and alateral support buoy coupled between the lateral tether portion and thevertical tether portion.
 7. The system of claim 6, wherein the lateralsupport buoy substantially provides buoyancy for at least one of thelateral tether and the vertical tether.
 8. The system of claim 6,wherein at least one of the lateral tether and the vertical tethercomprises an attached buoyancy device coupled thereto.
 9. The system ofclaim 6, wherein at least one of the lateral tether and the verticaltether has built in buoyancy.
 10. The system of claim 6, furthercomprising a second buoyant tether coupled to the array of buoys tosecure the array of buoys to the object.
 11. The system of claim 10,wherein the second buoyant tether comprises: a second lateral tetherportion coupled to the array of buoys; a second vertical tether portionto attach to the ocean floor; and a second lateral support buoy coupledbetween the second lateral tether portion and the second vertical tetherportion.
 12. The system of claim 11, wherein the buoyant tether and thesecond buoyant tether are coupled to the array of buoys about oppositesides.
 13. The system of claim 6, further comprising a second array ofbuoys coupled to the array of buoys.
 14. The system of claim 13, furthercomprising a second buoyant tether coupled to the second array of buoys,wherein the second buoyant tether comprises: a second lateral tetherportion coupled to the second array of buoys; a second vertical tetherportion to attach to the ocean floor; and a second lateral support buoycoupled between the second lateral tether portion and the secondvertical tether portion.
 15. The system of claim 14, wherein the buoyanttether and the second buoyant tether are coupled about opposite ends ofthe array of buoys and the second arrays of buoys.
 16. The system ofclaim 15, wherein the vertical tether portion and the second verticaltether portion[s] are configured to facilitate changing an orientationof the array of buoys and the second arrays of buoys when attached tothe ocean floor.
 17. The system of claim 14, wherein the lateral tetherportion and the second lateral tether portion are coupled to therespective array of buoys such that the lateral tether portion and thesecond lateral tether portion are substantially orthogonal to oneanother.
 18. The system of claim 1, wherein at least one of the basebuoy and the plurality of movable buoys comprises a hydrodynamic surfaceto reduce drag as water passes around the buoy.
 19. The system of claim1, wherein the vertical members and the plurality of movable buoys areconfigured to maintain an orientation of the plurality of movable buoysrelative to the vertical members.
 20. The system of claim 1, wherein thearray of buoys further comprises a ballast portion operable with thebase buoy to move in a pendulum motion in response to a wave in the bodyof water, wherein the base buoy is substantially maintained above theballast portion.
 21. The system of claim 20, further comprising anextension member coupled to the base buoy and the ballast portion tosuspend the ballast portion below the base buoy.
 22. The system of claim21, wherein the extension member is extendable and retractable to vary adistance between the ballast portion and the base buoy to vary stabilityof the array of buoys.
 23. The system of claim 20, wherein the ballastportion is configured as a rudder to facilitate steering the array ofbuoys through the water.
 24. The system of claim 1, wherein the buoyanttether includes submerged buoys adapted to provide tension between thearray of buoys and the object.
 25. A method for obtaining energy from awave in a body of water, comprising: obtaining an array of buoysincluding: a framework having a plurality of vertical members, a basebuoy coupled to the framework to support the framework in a body ofwater and maintain the vertical members in a vertical orientation, aplurality of movable buoys, wherein each of the plurality of movablebuoys is movably disposed about a different one of the plurality ofvertical members and configured to move relative to the respectivevertical members and the base buoy in response to a wave in the body ofwater, and an energy conversion device operable with each of theplurality of movable buoys to generate power from movement of themovable buoys relative to the vertical members; coupling a buoyanttether to the array of buoys, the buoyant tether including a tensioner;disposing the array of buoys in the body of water; and securing thearray of buoys to an object, wherein the tensioner is adapted tofacilitate a change in length of the buoyant tether between the array ofbuoys and the object to compensate for changing ocean height due towaves and tides, and wherein the buoyant tether comprises a primarybuoyant tether and a plurality of secondary tethers coupled to theprimary tether via the tensioner to facilitate load sharing among thesecondary tethers.
 26. The method of claim 25, wherein the buoyanttether comprises: a lateral tether portion to couple to the array ofbuoys; a vertical tether portion to attach to an ocean floor; and alateral support buoy coupled between the lateral tether portion and thevertical tether portion.
 27. A system for obtaining energy from surfacewaves, comprising: an array of buoys including a framework having aplurality of vertical members, a base buoy coupled to the framework tosupport the framework in a body of water and maintain the verticalmembers in a vertical orientation, a plurality of movable buoys, whereineach of the plurality of movable buoys is movably disposed about adifferent one of the plurality of vertical members and configured tomove relative to the respective vertical members and the base buoy inresponse to a wave in the body of water, and an energy conversion deviceoperable with each of the plurality of movable buoys to generate powerfrom movement of the movable buoys relative to the vertical members; anda buoyant tether coupled to the array of buoys to secure the array ofbuoys to an object, the buoyant tether including a tensioner adapted tofacilitate a change in length of the buoyant tether between the array ofbuoys and the object to compensate for changing ocean height due towaves and tides, wherein the array of buoys further comprises a ballastportion operable with the base buoy to move in a pendulum motion inresponse to a wave in the body of water, wherein the base buoy issubstantially maintained above the ballast portion, and furthercomprising an extension member coupled to the base buoy and the ballastportion to suspend the ballast portion below the base buoy, wherein theextension member is extendable and retractable to vary a distancebetween the ballast portion and the base buoy to vary stability of thearray of buoys.
 28. The system of claim 27, wherein the buoyant tetheris a utility line carrying at least one of electricity, pumped fluid, orgas.
 29. The system of claim 27, wherein the buoyant tether comprises anattached buoyancy device coupled thereto.
 30. The system of claim 27,wherein the buoyant tether has built in buoyancy.
 31. The system ofclaim 27, wherein the buoyant tether comprises: a lateral tether portioncoupled to the array of buoys; a vertical tether portion to attach to anocean floor; and a lateral support buoy coupled between the lateraltether portion and the vertical tether portion.
 32. The system of claim31, wherein the lateral support buoy substantially provides buoyancy forat least one of the lateral tether and the vertical tether.
 33. Thesystem of claim 31, wherein the second buoyant tether comprises: asecond lateral tether portion coupled to the array of buoys; a secondvertical tether portion to attach to the ocean floor; and a secondlateral support buoy coupled between the second lateral tether portionand the second vertical tether portion.
 34. The system of claim 33,wherein the buoyant tether and the second buoyant tether are coupled tothe array of buoys about opposite sides.
 35. A system for obtainingenergy from surface waves, comprising: an array of buoys including aframework having a plurality of vertical members, a base buoy coupled tothe framework to support the framework in a body of water and maintainthe vertical members in a vertical orientation, a plurality of movablebuoys, wherein each of the plurality of movable buoys is movablydisposed about a different one of the plurality of vertical members andconfigured to move relative to the respective vertical members and thebase buoy in response to a wave in the body of water, and an energyconversion device operable with each of the plurality of movable buoysto generate power from movement of the movable buoys relative to thevertical members; and a buoyant tether coupled to the array of buoys tosecure the array of buoys to an object, the buoyant tether including atensioner adapted to facilitate a change in length of the buoyant tetherbetween the array of buoys and the object to compensate for changingocean height due to waves and tides, wherein the array of buoys furthercomprises a ballast portion operable with the base buoy to move in apendulum motion in response to a wave in the body of water, wherein thebase buoy is substantially maintained above the ballast portion, whereinthe ballast portion is configured as a rudder to facilitate steering thearray of buoys through the water.
 36. The system of claim 35, whereinthe buoyant tether is a utility line carrying at least one ofelectricity, pumped fluid, or gas.
 37. The system of claim 35, whereinthe buoyant tether comprises an attached buoyancy device coupledthereto.
 38. The system of claim 35, wherein the buoyant tether hasbuilt in buoyancy.
 39. The system of claim 35, wherein the buoyanttether comprises: a lateral tether portion coupled to the array ofbuoys; a vertical tether portion to attach to an ocean floor; and alateral support buoy coupled between the lateral tether portion and thevertical tether portion.
 40. The system of claim 39, wherein the lateralsupport buoy substantially provides buoyancy for at least one of thelateral tether and the vertical tether.
 41. The system of claim 39,wherein the second buoyant tether comprises: a second lateral tetherportion coupled to the array of buoys; a second vertical tether portionto attach to the ocean floor; and a second lateral support buoy coupledbetween the second lateral tether portion and the second vertical tetherportion.
 42. The system of claim 41, wherein the buoyant tether and thesecond buoyant tether are coupled to the array of buoys about oppositesides.